Taking a step toward that leaf-like performance, researchers at Osaka Metropolitan University have developed an artificial photosynthesis system that produces formic acid from carbon dioxide and water using solar power.

The interesting bit is not simply that it makes formic acid. It is that the device is designed to keep producing it more steadily throughout the day without relying on the battery-based control hardware normally used to tame unstable sunlight. The system uses a redesigned electrolyzer that can partially self-regulate. In testing, the setup produced a pure aqueous formic acid solution under real sunlight, even as the light intensity changed. To understand how, there are a couple of foundational technologies to quickly unwrap.